Control system



March 1934- c. w. Li TTLER 1,951,426

CONTROL SYSTEM Filed Oct. 28, 1930 2 Sheets-Sheet 2 INVENTOR WWW Patented Mar. 20, 1934 common srs'rm Carl W. Littler-,Aliquippa, Pa., assignor to Jones & Laughlin Steel Corporation, Pittsburgh, Pa, a corporation of Pennsylvania Application October 28, 1930, Serial No. 491,679

17 Claims. (01. 256-415) My invention relates to metal working and, in particular, to the rolling ofmetal, although it is not limited thereto since it may be applied with equal success to other processes of metal working.

It is well known in the rolling art that there is a definite range of temperature which is an optimum for rolling. The material should not be above a certain maximum rolling temperature or below a definite minimum temperature. For

this reason, it is highly desirable toprevent the.

passage to the rolling mill of billets whose temperature is outside the rolling limits. For convenience of description, I hereinafter refer to the piece being rolled as a billet, but it will be understood that the invention is equally applicable to other pieces, such as rods, strips, or shapes.

The present invention provides a means for controlling the movement of heated billets from the heating furnace to the rolling mill in accordance with the temperature of the billets as indi-.

direction, advances the billets from the furnace to.

the rolls.

I provide a portion of the roll table with an independent drive which is under the joint control of the roller and means responsiveto the temperature of the billet as measured by the radiant energy emitted. As a temperature responsive means, I employ the photo-electric cell. This device, of course, is responsive to the intensity of the illumination impinging thereon. Since the luminous energy radiated by the hot billet, however, is, generally speaking, proportional to its temperature, the energy radiated by the billet affords a satisfactory measure of temperature. Through suitable relays, the photo-electric cell cooperates with the ,motor control apparatus which is under the manual control of the roller, to prevent the separately driven section of the roll table from advancing the billet to the rolls if it is too hot or .too cool forrolling. In this way, I prevent the passage to the rolls of any billets whose temperature is not within the proper range for rolling.

For a complete understanding of the invention, reference is made to the accompanying drawings illustrating a present preferred embodiment of the invention. In the drawings.

Figure 1 is a diagrammatic plan-view of a rolling mill including the present invention; and

' Figure2illustratesaport1onofFigure1toan enlarged-scale and includes the circuit diagrams for the control elements.

Referring in detail to the drawings, there is shown a set of charging skids'lO, a charging table 11, and a dragover 12. The function of these units, of course, is to position billets in the charging end of a furnace such'as that indicated at 13.

A pusher 14 advances the billets through the fur-- nace toward the discharge end thereof from which the heated billets are removed by an ejector 15. The discharged-billets are received on a transfer table 16 and are adapted to be passed to a scale remover 17 and placed on a roll table 18 by a dragover 19. The apparatus so far described represents merely standard practice in the arrangement and construction of a rolling The roll table 18 is divided into a plurality of separately driven sections 20, 21, and 22. Separate driving motors 23, 24, and are provided for driving these sections of the table through the usual line shaft and beveled gearing. Ad-' jacent the end of the section 22 is located a stand of rolls 26 which is adapted to be driven in the usual manner by a motor 27 through the couplings 28 and 29 and the pinions 30.

The motors 23 and 25 are under the control of the roller; through the usual manual control mechanism, not shown. The motor 24 is adapted to be controlled by a manual control mechanism 31 and has its control relays and contactors mounted on a panel 32. .The controller 31, however, is not the' sole means for controlling the motor 24; The control circuit forcausing forward rotation of the rolls in section 21 of the roll. table includes means responsive to the temperature of the billet to be rolled.

The temperature-responsive means includes a housing 33 partially enclosing section 21 of'the roll' table. A funnel-shaped housing 34 connects the housing 33 to a .tube 35 leading to (21- closures 36 and 37. Within the housing 34 lenses/3 8 are positioned for collecting the rays of light emitted by the glowing billet positioned, for example, at 39 on the roll table, into a beam. At the junction of the duct 34 with the tube 35, a reflecting prism 40 is located which serves to split the beam and-divert a portion thereof into each of the enclosures- 36 and 37. Between the prism 40 and the enclosures 36 and 37 adjustable light screens or filters 41 and 42 are positioned.

Within the enclosures 36 and 3'7, and in light receiving relation to the prism 40, photo-electric cells 43 and 44 are'arranged, The photo-electric cells 43 and 44, through electron relays 45 and 46,

moved onto the table 11 by the dragover 12 and trol mechanism (not shown) the roller then the control mechanism 31 ineflective to cause forward movement of the section 21 of the rolltable The screen 41 is preferably adjusted so that the cell 43 will be rendered operative only when a billet having a temperature greater than the maximum rolling temperature passes through the enclosure 33. Similarly, the screen 42 is ad-v Justed so that the cell 44 will operate whenever a billet having a temperature greater than the minimum rollingtemperature stands in light radiating position relative to the duct 34, but will not operate if the temperature is below. that. valuegns will be explained in greater detail later, ,the photo-electric cells prevent forward movement of the billet so that, unless the billet temperature is within the rolling range, it will not be'per'mittedto pass to the rolls. The operation of the system will now be described by tracing the pathof the heated billet through all its movements preliminary to rolling. Billets delivered to the charging skids 10 are conveyed into the charging end of the furnace. By means of the pusher 14, they are passed through the furnace, and, when they reach the dischargeen'd thereof, they aredischarged singly by the, ejector 15 onto the transfe'r table 16. From' the transfer table 16, a heated billet is. shifted-to the section of the roll table 18 by means of the dragover 19, after passing through the scale remover 17. Through the usual constarts the motor 23 to cause the rolls of the sec tion 20'to turn so that the billet isadvanced toward the rolls 26 which. are driven continuously by the motor 27. The motor 24 for driv-- ing the section 21 of the roll table 18 is normally j inoperative until a billet of proper rolling temperature passes through the housing 33.- The section 20 of the roll table 18 is, therefore, effec tive only to advance the billet to -a position such as indicated at 39. In this position, the billet is in light transmitting relation to the lenses 38 and throughthe prism 40 to the photo-electric cells 43 and 44.

It will now be-assumed that the billet at the position 39 has been over-heated and has a temperature exceeding the maximum optimum rolling "temperature. As previously stated, the screen 41 is adjusted so that the cell- 43 operates under these conditions. Since the screen 42 is adjusted so that the cell 44 will operate when receiving light of much less intensity, the cell 44 "also operates at this time.

Thelight impinging on the cells 43 and 44, therefore, causes a how of current between the electrodes thereof. One of the electrodes of each 4 cell is connected ,to a control electrode of the electron relays 455m 46. The control electrodes designated by the numerals 45a and 46a,

respectively. When the proper charge has been established on the control electrodes 45:; and 46a by the flow of current-from the photo-electric cells 43 and 44, current passes through the electron relays 45 and 46, between their main electrodes 45b, 45c, and 46b and 46c. The main electrodes of the relays 45'and 46 are connected in a series circuit including the windings of the transformers 49 and 50. The primary windings relays 47 and 48 and the secondary windings-of "provide a suitable voltage for lays 45, 46, 47, and 48.

The relay 47 has two back contacts 47a and 47b. The relay 48 has two front contacts; 48a and 48b. Contacts 47b and 48b of the relays are connected in a series circuit 51- extending to the panel 32. The devices and connections making up the panel 32 are not illustrated in detail since these arealready well known. The circuit 51 I may 'be connectedto the control relayson the panel 32 for causing forward movement of the rolls in section 21 of the roll table in any desired manner so that, as long as the circuit 51 is open,

operating the re- 47 and 48 will open the circuit at 47b and the closing .of the circuit at 48b will not be efiective to permit forward movement of the billet under the control of-the roller operating the controller 31.

In addition to positivelycontrol'ling the operation of the section 21 of the roll table, I also provide signal lamps 52 and 53 controlled, respectively, by the relays 47 and 48. The signal lamps are connected to a source of current 54- in series with the contacts 47a and 48a of-the relays. As

illustrated, the lamp 52 is extinguished when the billet is too hot and the lamp 513 is illuminated.

- If the billet is too hot, as assumed at the beginning, it may be permitted to cool while standing onthe section 21 of the roll table, or it may be returned to the section 20 for this p rpose. Preferably, reverse movement of the bi let on the section 21 is not interfered with by the operation of the photo-electric cells. If thebillet is permitted to reston the section 21 while cooling, v

the cell 43' will become inoperative when the billet has cooled to within the proper limits for rolling. When the photo-electric cell 43 becomes inoperative, the relays 45 and 47 are deenergized.

The adjustment of the screen 42, however, is such the billet to the rolls 26 over the sections 21 and.

22 of the roll table. Similar results would, of course, follow if the billet initially had the proper temperature. --In such case, the cell 43 and the relays 45 and 47 remain unoperated while the cell 44in the relays 46 and 48 alone would operate. Under these conditions, the lamp 53 would be energiz'ed, as well as the lamp 52. The roller would i know that, when both lamps are illuminated, the

temperature of the .billet is within the rolling arange. Obviously, other arrangements of ,the

signal lampsrni'ght be employed or signal devices other than lamps.

. If the billet is initially too coolfor rolling, both the photo-electric cells 43 and 44 would remain inoperative and thecircuit 51 will be open-at the contact 481 of therelay48. Forward movement of the conveyor will be prevented and only the v .signal lamp 52 will be energized. Since the billet is too cool "for rolling, it must be returned to a reheating furnace '55 by reversing the sections 21' and 20 of the roll table 18 and by driving a roll table 56 by means of a motor 57 under manual control of the roller. When the billet has been reheated, it may again be forwarded to the section 21 of the roll table and, if it has been heated to the proper temperature, it may be passed onto the rolls 26.

It will be apparent from the foregoing that the invention provides means positively preventing the movement of billets to the rolls if their temperature is outside the proper rolling range. In addition, the roller is provided with signals to indicate the temperature of the billet so that he may be governed accordingly as to subsequent movement thereof. The temperature-responsive apparatus may be adjusted to a very high degree of accuracy and the rolling process may, therefore, be carried out with better results than by the old method, in which the temperature of the billet was more or less an unknown factor.

Although I have illustrated and described herein but one present preferred embodiment of the invention, I do not intend to be limited to the specific details of the disclosure since other embodiments may be resorted to without sacrificing the advantages of the invention nor departing from the spirit thereof as set forth in the appended claims.

Where I have used the term forward" in the claims to describe a directionof operation of the roll table, I mean thereby the direction toward the rolls.

I claim:

1. Apparatus for working on heated metal comprising means for advancing metal into working position, and means including an element responsive to the radiations. from the metal for preventing operation of said first-mentioned means.

2. The combination with a roll table for handling hot metal, of an enclosure adjacent the table, a lens therein for collecting the rays radiated by the metal into a beam, means for dividing said beam and diverting portions thereof onto photo-cells, means for calibrating said cells to operate at the upper and lower limits of the optimum working temperature of the metal, and means controlled by said cells for controlling the forward operation of said table.

3. The combination with a mill for rolling hot metal, means for feeding metal to the mill and a controller for said means, of means responsive to the radiant energy emitted by the metal for rendering the controller ineffective.

4. Metal working apparatus comprising a roll- 3 ing mill, 9. roll table for conveying heated metal to the mill, a motor drive for the roll table, and means including an element responsive to the energy radiating from the heated metal for preventing the operation of said drive.

5. Metal working apparatus including a con-- photo-cell adjacent said table and subject to the energy radiating from said metal, and means controlled by said photo-cell for controlling the operation of the table drive.

8. In a rolling mill, a roll table, a motor drive therefor, manual control means for said drive and means including an element responsive to the degree of radiance of hot metal on said table for rendering said control means ineffective to cause the metal to be advanced to the mill.

9. The combination with a mass of heated metal and means for moving it, of means including an element responsive to the energy radiated thereby for preventing the operation of the, moving means.

10. In combination, a conveyor, a mass of hot metal thereon to be moved along on the conveyor, a photo-cell responsive to the energy radiated from the metal, and means controlled thereby for preventing operation of the conveyor.

11. A rollling' mill including a roll table, a motordrive therefor, a photo-cell subject to the energy radiated by heated metal on said table,

and relays connected in circuit with and controlled by said cell for controlling forward operation of said drive.

12. In a control system for a rolling mill roll table, photo-cells responsive to energy radiated from hot metal to be rolled, screens intercepting the energy radiations, and means operated by said cells in response to different temperatures of the metal for controlling the operation of. the table.

13. In a mill for working heated metal, and means for forwarding metal to the mill, means responsive to the radiant energy emitted by the metal, and means controlled by said secondmentioned means, for preventing operation of said first-mentioned means, precluding movement to the mill of metal below a predetermined rolling temperature.

14. The combination with apparatus for working hot metal, and means for forwarding metal to the working apparatus, of means responsive to the energy radiating from the metal, and means controlled by said second mentioned means for preventing the operation of said first-mentioned means, precluding supply of improperly heated metal to the working apparatus.

15. The combination with a metal working apparatus and means for forwarding metal thereto,

of,a light-sensitive cell responsive to the energy 125 radiated by apiece of hot metal, and means operated thereby for preventing the operation of said first-mentioned means, precluding movement of the metal through the apparatus if its temeration ofthe feeding means to advance metal through the apparatus.

17. In a rolling mill, a roll table, a motor drive therefor and control mechanism for the drive including photo-cells subject to energy radiating from metal on the table and means for determining the operation of the cells at the upper and lower limits, respectively, ofv the optimum rolling temperature, and means controlled by the cells for preventing forward operation of the table if the temperature of the metal is outside said limits.

. CARL W. LITILER. 

